Change in Inclusions after Mg Deoxidation Process

摘要

In the present paper,effect of Mg deoxidation on formation of inclusions in steel plate for shipbuilding is studied.After Mg deoxidation,the compositions of inclusion can be changed,with higher MgO content at its center,and higher MnS and CaS content on its surface.For the precipitates with the diameter smaller than 100nm,their number in the steel plate after Mg deoxidation is very large.During the welding process with the high heat input for the steel plate,these kinds of inclusions effectively inhibit the growth of austenite grain and enhance the formation of intragranular ferrite in the heat affected zone.The toughness of the heat affected zone has been greatly improved.